Abstract: Based on the advantages of the dual mode defected ground structure resonators (DDGSR),a multi band bandpass filter through nested DDGSRs is formed. With the help of the transmission zero introduced by stubs in the feedlines, a high selectivity quad band bandpass filter (BPF) with wide upper stopband is presented. One DDGSR consists one slot line resonator (SLR) and a defected stepped impedance resonator (DSIR). Using the four nested DDGSRs, a quadband BPF located at GPS(1.57GHz)、DCS(1.8GHz)、WLAN(2.4GHz)、WiMAX(3.5GHz)bands has been simulated and the structure parameters have been optimized using simulation software. Also, an experimental circuit has been fabricated. The measured results show that the quad band BPF operates at 1.58/1.8/2.42/3.58 GHz, with fractional bandwidths of 8.2/5/5.4/6.7% and measured minimal insertion losses of 1. 2/1. 6/1. 6/2.6 dB. Good agreement between the simulated and measured results validates the design approach.